Field of the Invention
The present invention relates to alpha-amylase variants, polynucleotides encoding the variants, methods of producing the variants, and methods of using the variants.
Description of the Related Art
Alpha-amylases (alpha-1,4-glucan-4-glucanohydrolases, E.C. 3.2.1.1) constitute a group of enzymes, which catalyses hydrolysis of starch and other linear and branched 1,4-gluosidic oligo- and polysaccharides.
There is a long history of industrial use of alpha-amylases in several known applications such as detergent, baking, brewing, starch liquefaction and saccharification e.g. in preparation of high fructose syrups or as part of ethanol production from starch. These and other applications of alpha-amylases are known and utilize alpha-amylases derived from microorganisms, in particular bacterial alpha-amylases.
WO 2000/060058 discloses the two alpha-amylases AAI-6 and AAI-10 (as SEQ ID NOs 2 and 4 which in the present application are SEQ ID NOs 1 and 2) and discloses thermostable variants thereof.
For environmental reasons it has been increasingly important to lower the temperature in washing, dishwashing and/or cleaning processes. However, most enzymes including the amylases of AAI-6 and AAI-10 have a temperature optimum which is above the temperature usually used in low temperature washing. Alpha-amylase is a key enzyme for use in detergent compositions and its use has become increasingly important for removal of starchy stains during laundry washing or dishwashing. Therefore, it is important to find alpha-amylase variants, which retain their wash performance, stain removal effect and/or activity when the temperature is lowered. Thus, it is desirable to have amylolytic enzymes that can function under low temperature and at the same time preserve or increase other desirable properties such as specific activity (amylolytic activity), stability and/or wash performance.
Thus, it is an object of the present invention to provide alpha-amylases variants which have high performance, in particular high wash performance, at low temperatures and/or which have high stability in detergent compositions and/or which have high amylase activity after storage in detergents.
The present invention provides alpha-amylase variants with improved properties compared to its parent.